Foam flotation



Patented'Jan. 6, 1931 UNITED STATES PATENT OFFICE JULIUS EISELE, ROBERT GRIESSBACH, AND CLAUS HEUCK, OF LUDWIGSHAFEN-ON- THE-RHINE, GERMANY, ASSIGNOBS TO I. G. FARBENINDUSTBIE AKTIENGESELL- SGHAIT, OF FRANKFOB'1 ON-THEJIAIN, GERMANY, A CORPORATION OF GERMANY roan rtorarron No Drawing. Application filed lebruary 9, 1928, Serial No. 253,214, and in Germany February 16, 1927.

The foam flotation process for the preparation of coal, ores, slags and the like and more especially for the separation of inferior coals and low-grade ores from ash constituents, impurities and gangue, is carried out with flotation agents, which should have theproperty, on the one hand, of effectually wetting the material to be floated, and, on the other, of generating foam. f The flotation agents hitherto-employed for this purpose, such as parafiins, tars, phenols and aromatic amines,

combine these two properties only imperfectly if at all, and for this reason the addition of special foam producers, such as pine oils,

. crude turpentines, saponins, sulfonic acids or salts of same, and the like is required.

We have found that the products obtained by oxidizing hydrocarbons more especially paraflins, or waxes and the like at compara tively low temperatures, generally not exceeding 200 (3., so that no decomposition occurs, can be employed to great advantage as flotation agents. These substances possess the property of floating coal and ores and especially sulfid ores, in aqueous suspensions, so

that a considerable concentration of highgrade coal or ore is obtained in the foam.

These products also act as powerful foaming agents, audit is therefore unnecessary to add any further foam producers. Most of.

E mampl e 1 Finely ground brown-coal, or brown-coal.

dust, with over 23 per cent of ash content in proportion to the dry substance, is treated by the flotation process in aconically shaped apparatus of any known kind, air being passed through. The flotation agent added consists of a readily volatile oxidation product of paraifin wax, neutralized with ammonia, the amount employed being 1 per cent of the weight of drysubstance in the material treated. After a short treatment, the

dry substance.

resulting coal concentrate is drawn oil, and its ash content is found to have been reduced by more than 50 per cent.

E mample 2 A difiicultly volatile oxidation product of Montan wax, neutralized with ammonia, is employed as a flotation agent in the manner described in Example 1-. In this case also, the original ash content of the coal is reduced to less than one half.

'Emwmple 3 g Sandy pyrites is subjected to flotation by adding a diflicultly volatile, neutralized oxidation product of paraflin wax,'the amountof the agent being 1 per cent the weight of the ore. The pyrites content in the foam is three I times that originally present in the sandy pyrites.

Example 4 Finely ground brown-coal with .a content dry substance is subjected to flotation after of 46 per cent of ashes in proportion to the admixing a diflicultly volatile oxidation prodnot of paraflin wax in an amountof 1 per cent of the dry weight of the brown-coal to be treated. After a short treatment a concentrate of coal is drawn oif, the content of ashes of which amounts to only 16 per cent of the 4 the oxidation at an elevated temperature not exceedin 200 C. of a material, comprising hydrocar ons of high molecular weight, then passing a. current of a gas through the mix ture and separating the resulting froth;

.2. The process of foam flotation, which comprises intensely mixing an aqueous pulp of the material to be treated with a product of the oxidation at an elevated temperature not exceeding 200 C. of a material comprising paraflin wax, then passing a current of a gas throu h the mixture and separating the resulting roth.

3. The process offoam flotation, which a comprises intensely mixing an aqueous pulp of the material to be treated with a product of the oxidation at an elevated temperature not exceeding 200 C. of a material mainly 5 consisting of hydrocarbons of a high molecular weight, and with an amount of a basic agent at the most equivalent to the quantity of free acids contained in the said oxidation product, then passing a current of air through m the resulting mixture and separating the resuiting froth.

4. The process of foam flotation, which comprises intensely mixing an aqueous pulp of the material to be treated with a product of the oxidation at an elevated temperature not exceeding 200 C., and with ammonia, then passing a current of a gas through the resultin nuxture and separating the resulting hot 1. 2o 5. The process of foam flotation, whic comprises intensely mixing an aqueous pulp of the material to be treated with about 1 per cent its weight of a product of the oxidation at an elevated temperature not exceeding 200 C. of paraffin wax, and with a quantity of ammonia exactly neutralizing the free acids contained in the said oxidation product, then passing a current of air through the resulting mixture and separating the resulting froth. In testimony whereof we have hereunto set our hands.

JULIUS EISELE. ROBERT GRIESSBACH. CLAUS HEUGK. 

